Defrance had an extensive and successful military career in the French Revolutionary Wars and the Napoleonic Wars. After the First Battle of Zurich, he refused a battlefield promotion to brigadier general, asking instead for a cavalry regiment; he received command of the 12th Regiment of Chasseurs-a-Cheval (light cavalry) as Chef-de-Brigade, a rank equivalent to colonel. He led this brigade in the campaigns of 1799–1800 in southwestern Germany and northern Italy. By 1805, he had been promoted to brigadier general. At the Battle of Austerlitz and the Battle of Jena-Auerstadt, he commanded a cavalry brigade of carabiniers in Étienne Marie Antoine Champion de Nansouty's First Division. By the Battle of Borodino in September 1812, he had been promoted to general of division, commanding the 4th Cuirassier Division of Nansouty's reserves, where they charged the Shevardino redoubt. He fought his way across Germany to the Rhine River after the French loss at Leipzig and participated in the Six Days Campaign.

In the Hundred Days, he commanded part of Jean Maximilien Lamarque's Army of the West. At the second Bourbon Restoration, he retained his titles and honors and subsequently held several command posts until retirement in 1829. He died in 1855.